If your vet says your cat's bilirubin count is high, that could mean a number of things. If you're lucky, hyperbilirubinemia, the technical term for too much bilirubin, results from an easily treatable issue. The dangers of high bilirubin all depend on the cause.
Orangey-yellow in color, bilirubin comes from broken down hemoglobin from aged red blood cells. Older red blood cells in the body are taken out of circulation by cells called macrophages from the spleen and liver. The macrophages produce the bilirubin, releasing them into the bloodstream where they join up with albumin, a protein. Once bonded, they go to the liver, where cells take the bilirubin out of the albumin and send it to the gall bladder and bile ducts. It ends up with bile in the small intestine to aid in digestion. If there is excess bilirubin in Fluffy's system, he ends up with jaundice.
The most common symptom of too much bilirubin in the system is jaundice. The whites of your cat's eyes, his gums and skin all take on a yellow tone. He's also lethargic, not eating, drinking and peeing more and his stools resemble tar. His urine can turn quite orange. However, jaundice is a symptom, not a disease in itself, so your vet must figure out exactly what's wrong with your cat.
While jaundice often results from liver disease, it's not the only cause. Cats with high bilirubin levels and jaundice might suffer from lymphoma, autoimmune hemolytic anemia, pancreatitis, internal parasites, gall bladder inflammation and bile flow obstruction. Liver ailments causing jaundice include hepatic lipidosis, better known as fatty liver disease. Hepatic lipidosis can be reversed with good nutritional support, even if that means force-feeding. Liver cancer can also cause jaundice, but here the prognosis isn't very good.
To figure out why Fluffy turned yellow, your vet conducts a careful physical exam and asks you about the cat's medical history. She'll collect blood and urine for basic testing, which includes a complete blood count and urinalysis. Your vet might recommend X-rays or an ultrasound, as well as testing for serum bile acids and for parasites in the blood. If results indicate liver disease, she might perform a liver biopsy. Treatment, and your cat's prognosis, all depends on what's causing his high bilirubin levels.
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